Safety helmet



FIG. 1 is a front side perspective view showing my new design for a safety helmet;

FIG. 2 is a rear side perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a perspective view thereof; the visor shown in broken lines forms no part of the claimed design. 

I claim the ornamental design for a safety helmet, as shown and described. 